Starts to talk back concerning energy cut (1-4)
I believe the answer is:
t-bone
'cut' is the definition.
(I have seen 'Cut of steak' mean 't-bone' so perhaps 'cut' could also mean 't-bone')
'starts to talk back concerning energy' is the wordplay.
'starts to' indicates taking the first letters.
'concerning' becomes 'on' (both can mean 'in relation to').
'energy' becomes 'e' (physics symbol as in E=mc2).
The first letters of 'talk back' is 'tb'.
'tb'+'on'+'e'='T-BONE'
(Other definitions for t-bone that I've seen before include "Kind of steak" , "Choice piece of loin steak" , "Cut of beef" , "Choice cut of steak" , "Type of steak" .)